Nonwoven products have gained continued acceptance in the industry for a wide range of applications, particularly as replacements for woven fabrics. The term “nonwoven” refers to textile structures produced by bonding or interlocking fibers (or both) accomplished by mechanical, chemical, thermal or solvent means, or even combinations thereof. Such textile structures do not include paper or fabrics that are woven, knitted or tufted. Typically, nonwoven materials are composed of simply a single layer of randomly oriented fibers. Examples of products employing nonwoven materials to date include facings or top-sheets in diapers, incontinent pads, bed pads, sanitary napkins, hospital gowns, cleaning towels, carpets, draperies and industrial and commercial goods, such as wipe cloths, tire cords, conveyor belts, and hospital fabrics. It is typically desirable to produce the nonwoven material so that it has the flexibility and hand softness of a textile, yet is as strong as possible.
Conventional processes for manufacturing nonwoven materials, such as nonwoven glass fiber materials employed in roofing shingles, as well as other products, typically follow a similar approach. Specifically, a slurry of glass fibers is made by adding glass fiber strands to a pulper to disperse the fiber in the white water. The slurry mixture is then deposited onto a “forming wire” and dewatered to form a continuous wet nonwoven fibrous mat. To dewater the slurry, the water is drawn through the forming wire, leaving the fibers from the slurry randomly dispersed over the forming wire to form the mat. A binding agent may then be applied to the wet mat to bond the randomly dispersed fibers in their respective locations and directions. The mat material is then cut to a desirable size and dried. Alternative forming methods include the use of well-known “wet cylinder” forming, and “dry laying” using carding or random fiber distribution.
Although conventional nonwoven materials are typically stronger and resist tears more than woven materials, the density and/or number of fibers (i.e., the “weight” of the material) used to form the material often must be further increased to satisfy some intended uses. More specifically, while a nonwoven mat may be stronger than a similar woven mat, the nonwoven mat's weight may need to be increased to accommodate even further stresses. Unfortunately, as the weight of nonwoven materials is increased to accommodate higher stresses, the cost of manufacturing also increases.
It is thus highly desirable to provide for a nonwoven material that can be manufactured with less weight than conventionally available mats, but with equivalent strengths. To do so would allow for advantageous decreases in the cost of manufacturing an adequately strong nonwoven material.